Assembly system for orthopedic components

ABSTRACT

An assembly system configured to seat a first orthopedic component having either a male taper or a female taper with a second orthopedic component having the other of a male taper or a female taper. In one embodiment, the assembly system includes a taper seating connector having a fastener and a bushing moveable retained on the fastener. The fastener may be connected to the first orthopedic component and the bushing may be positioned adjacent the second orthopedic component. The corresponding tapers on the first and second orthopedic components may be configured to secure the first and second orthopedic components together. Thus, by exerting a sufficient force on the bushing, the bushing will move along the fastener, transferring the force to the second orthopedic component. In this manner, the corresponding tapers of the first and second orthopedic components may be seated.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an assembly system, and, moreparticularly, to an assembly system for assembling orthopediccomponents.

2. Description of the Related Art

Orthopedic components, such as prostheses, are commonly utilized torepair and/or replace damaged bone and tissue in the human body. Forexample, hip prostheses may be implanted to replace damaged or destroyedbone in the femur and/or acetabulum and to recreate the natural,anatomical articulation of the hip joint. Additionally, prostheses maybe formed as modular prostheses. Modular prostheses have severalindividual, distinct components which are connected together to form afinal, implanted prosthesis.

To connect the individual modular components together to form the final,implanted prosthesis, specialized tools are often needed. Depending onthe design and connecting mechanism utilized in a specific modularprosthesis system, the specialized tools needed to connect theindividual modular components may only function with a single modularprosthesis system. Therefore, a different set of tools are needed foreach modular prosthesis system.

SUMMARY OF THE INVENTION

The present invention relates to an assembly system, and, moreparticularly, to an assembly system configured for assembling orthopediccomponents. The assembly system is configured to seat a first orthopediccomponent having either a male taper or a female taper with a secondorthopedic component having the other of a male taper or a female taper.In one embodiment, the assembly system includes a taper seatingconnector having a fastener and a bushing moveable retained on thefastener. The fastener may be connected to the first orthopediccomponent and the bushing may be positioned adjacent the secondorthopedic component. By exerting a sufficient force on the bushing, thebushing will move along the fastener, transferring the force to thesecond orthopedic component. This may cause the second orthopediccomponent to move toward the first orthopedic component. In this manner,the corresponding tapers of the first and second orthopedic componentsmay be seated.

In another embodiment, the assembly system includes a taper seatingtool. The taper seating tool may have a rod and a sleeve. The rod may beconfigured to attach to one of the fastener and the bushing of the taperseating connector. Similarly, the sleeve may be configured to abut theother of the fastener and the bushing. By moving the rod and/or thesleeve of the taper seating tool relative to one another, a force isexerted on at least one of the fastener and the bushing of the taperseating connector. When the taper seating connector is positioned asdescribed above with respect to the first and second orthopediccomponents, the force exerted by the taper seating tool on the taperseating connector will cause movement of the fastener and/or bushing ofthe taper seating connector. This movement will result in correspondingmovement of the first and/or second orthopedic components and theseating of the tapers of the first and second orthopedic components.

In one form thereof, the present invention provides a taper seatingconnector, including a fastener having a shaft and a hooked head, theshaft connectable to a first orthopedic component having one of a maletapered surface and a female tapered surface; a bushing retained on andmoveable along the shaft of the fastener, the bushing positionedadjacent a second orthopedic component when the fastener is connected tothe first orthopedic component, wherein the second orthopedic componenthas the other of the one of a male tapered surface and a female taperedsurface, whereby movement of one of the fastener and the bushing resultsin corresponding movement of one of the first and second orthopediccomponents.

In another form thereof, the present invention provides in combination ataper seating connector including a fastener and a bushing, the fastenerconnectable to a first orthopedic component having one of a male taperedsurface and a female tapered surface, the bushing positioned adjacent asecond orthopedic component when the fastener is connected to the firstorthopedic component, the second orthopedic component having the otherof the one of a male tapered surface and a female tapered surface; and ataper seating tool having a rod and a sleeve, wherein at least one ofthe rod and the sleeve are moveable relative to the other of the rod andthe sleeve, the rod configured for attachment to the fastener of thetaper seating connector, the sleeve configured to abut the bushing ofthe taper seating connector when the rod is attached to the fastener,whereby movement of at least one of the rod and the sleeve relative tothe other of the rod and the sleeve seats the male tapered surface andthe female tapered surface.

In yet another form thereof, the present invention provides a method ofseating orthopedic components including the steps of securing a taperseating connector having a fastener and a bushing to a first orthopediccomponent; positioning the taper seating connector adjacent a secondorthopedic component; attaching a taper seating tool to the seatingconnector; actuating the taper seating tool to force at least one of thefirst orthopedic component and the second orthopedic component towardthe other one of the first orthopedic component and the secondorthopedic component to seat the first and second orthopedic components.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective view of a taper seating tool according to oneembodiment of the present assembly system;

FIG. 2 is an exploded perspective view of a taper seating connector ofthe present assembly system;

FIG. 3 is a cross-sectional view of the taper seating connector of FIG.2;

FIG. 4 is an exploded perspective view of the taper seating tool of FIG.1;

FIG. 5 is a fragmentary exploded perspective view depicting the taperseating tool of FIG. 1, the taper seating connector of FIG. 3, a tibialplate, a tibial keel, and a tibia;

FIG. 6 is a fragmentary, partial cross-sectional view of the componentsof FIG. 5 depicting the corresponding tapers in an unseated position;

FIG. 7 is a fragmentary cross-sectional view of the components of FIG. 6taken along line 7 of FIG. 6; and

FIG. 8 is a fragmentary cross-sectional view of the apparatus of FIG. 7depicting the corresponding tapers in a seated position.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification set out hereinillustrates one preferred embodiment of the invention, in one form, andsuch exemplification is not to be construed as limiting the scope of theinvention any manner.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 4 depict taper seating tool 10 of the present assemblysystem. Taper seating tool 10 includes fixed handle 12 rigidly securedto fixed rod 14. Sleeve 16 surrounds at least a portion of fixed rod 14and is moveable along the longitudinal axis thereof. As described indetail below, when moveable handle 18 is rotated toward fixed handle 12,sleeve 16 moves downward along fixed rod 14 in the direction of arrow A.Thus, when fixed rod 14 is secured to head 20 of taper seating connector22 (FIGS. 2, 3, and 5-8) movement of sleeve 16 exerts a downward forceon bushing 24 of taper seating connector 22 to seat the correspondingtapers of orthopedic components, as described in detail below.

Referring to FIGS. 1 and 4, sleeve 16 of taper seating tool 10 isconnected to moveable handle 18 via work arm 26. Specifically,projections 28, extending from opposing sides of head 29 of sleeve 16,are received within grooves 30 (FIG. 4) formed in pivot portion 32 ofwork arm 26. Work arm 26 is retained on projections 28 by retention pins34. Additionally, moveable handle 18 is secured to work arm 26 at end36. Extending between pivot portion 32 and end 36 of work arm 26 isconnecting portion 38. Connecting portion 38 tapers along its length, sothat the width of connecting portion 38 decreases as connecting portion38 approaches end 36 of work arm 26. The taper of connecting portion 38allows for connecting portion 38 to bend when a sufficient force isexerted on moveable handle 18. This bending causes a substantially evendistribution of the stress, caused by the force exerted on moveablehandle 18, along the length of connecting portion 38 which provides atactile feedback to the surgeon as discussed in detail below.Advantageously, the substantially even distribution of stress along theentire length of connecting portion 38 may increase the useful life oftaper seating tool 10.

As shown in FIGS. 1 and 2, work arm 26 is further connected to fixedhandle 12 via link 40. Link 40 is connected to pivot portion 32 of workarm 26 via link pin 42, which extends through aperture 44 (FIG. 4) oflink 40 and apertures 46 of pivot portion 32 (FIG. 4). The opposing endof link 40 is connected to collar 48. Collar 48 substantially surroundsfixed rod 14 and is positioned adjacent to fixed handle 12. In oneexemplary embodiment, collar 48 and handle 14 are formed as an integral,monolithic component. Link 40 is attached to collar 48 by link pin 50extending through apertures in Y-arms 52, 54 (FIG. 2) and correspondingapertures in projections 56 of collar 48. Thus, when moveable handle 18is rotated toward fixed handle 12, work arm 26 is rotated about link pin42. Rotation of work arm 26 about link pin 42 causes pivot portion 32 tocorrespondingly rotate and exert a force on projections 28 of sleeve 16.This force results in movement of sleeve 16 in the direction of arrow A(FIG. 1).

As shown in FIG. 4, spring 58 and lock arm 60 are retained on link pin50 and secured between Y-arms 52, 54 of link 40. Spring 58 is connectedto and exerts a downward biasing force on lock arm 60, which isconfigured to pivot about link pin 50. As shown in FIG. 1, lock arm 60extends through slot 62 in end 36 of work arm 26. Lock arm 60 furtherincludes projection 64, which forms a detent with slot 62. Specifically,when moveable handle 18 is rotated about link pin 42 and advanced towardfix handle 14, lock arm 60 will be correspondingly advanced through slot62. As handle 38 continues toward handle 14, projection 64 will passthrough slot 62 and will move downward due to the biasing force ofspring 58. Thus, when movement of movable handle 38 ceases, the biasingforce of spring arm 61 will rotate work arm 26 and moveable handle 18away from handle 14. When end 36 of work arm 26 contacts projection 64of lock arm 60, further movement of moveable handle 18 away from fixedhandle 12 will be prevented.

Advantageously, the use of lock arm 60 causes a change in the center ofgravity of taper seating tool 10 and allows taper seating tool 10 tostand in an upright position on compression surface 66 (FIG. 4). Thus, asurgeon does not need to constantly hold taper seating tool 10 uprightwhen it is in the “locked” position. To unlock lock arm 60, the surgeonsimply lifts up on lock arm 60 with sufficient force to overcome thebiasing force of spring 58. Once projection 60 of lock arm 60 ispositioned within slot 62, moveable handle 18 may be rotated away formfixed handle 12 without encountering a further impediment.

To facilitate the attachment of taper seating tool 10 to taper seatingconnector 22 (FIGS. 2, 3, and 6-8), fixed rod 14 and sleeve 16 includecatch end 68 and passage 70, respectively. While depicted and describedherein as being configured for attachment to taper seating connector 22,shown in FIGS. 2 and 3, tapered seating tool 10 may also be configuredfor attachment directly to an orthopedic component or to a seatingconnector having a different configuration. Slot 72, extending partiallythrough catch end 68, is aligned with passage 70 to accommodate head 20of taper seating connector 22. Extending across slot 72 of catch end 68is bar 74. Bar 74 is configured for receipt within catch 76 of head 20,as described in detail below. Advantageously, by utilized catch end 68of fixed rod 14, taper seating tool 10 may be connected to any taperseating connectors having catch 76 or a similar attachment mechanism.Thus, taper seating tool 10 may be connected to taper seating connectors12 which are configured for different modular prosthesis systems. Thisallows for a single taper seating tool 10 to be interchangeably usedwith numerous prosthesis systems, lessening both the cost ofmanufacturing taper seating tool 10 and the cost of inventorying thesame.

Referring to FIGS. 2 and 3 and as discussed briefly above, taper seatingconnector 22 of the present assembly system includes fastener 78 andbushing 24. Fastener 78 includes shaft 80 and head 20 connected via neck82. Hook 81 of head 20 forms catch 76 therein. Additionally, threadedportion 84, having threads 86 thereon, is formed on shaft 80 of fastener78. Bushing 24 of taper seating connector 22 includes body 88 and barrel90. Knurled surface 92 of barrel 90 facilitates the grasping andpositioning of taper seating connector 22. Extending through bushing 24is aperture 94. As shown in FIG. 3, body 88 defines a portion ofaperture 94 having threads 96 formed therealong. Additionally, barrel 90of bushing 24 includes counterbore 98 which also forms a portion ofaperture 94.

Referring to FIG. 3, taper seating connector 22 is assembled bycapturing bushing 24 on fastener 78. Specifically, threads 86 offastener 78 are threaded along corresponding threads 96 through aperture94 of bushing 24. In one exemplary embodiment, once threads 86 havepassed along the entirety of threads 96, uppermost thread 86 is crimped,as shown at 100, to prevent the separation of fastener 78 and bushing24. With taper seating connector 22 configured as shown in FIG. 3,bushing 24 may move axially along shaft 80. Specifically, bushing 24 maymove from a position in which head 20 of fastener 78 contacts uppersurface 102 (FIG. 2) of bushing 24 to a position in which end surface104 contacts the uppermost portion of threads 86.

Advantageously, by altering the design of threaded portion 86 offastener 78 and bushing 24, taper seating connector 22 may be used withvarious modular prosthesis systems. Thus, by selecting the appropriatetaper seating connector 22 for a particular modular prosthesis system,taper seating tool 10 may be used in conjunction with the appropriatetaper seating connector 22 to seat the corresponding tapers of differentcomponents in the modular prosthesis system. This allows the seating ofa plurality of different taper designs with a single taper seating tool10.

By utilizing taper seating connector 22 in conjunction with taperedseating tool 10, orthopedic components having mating male and femaletapers may be assembled by seating the mating tapers as described indetail below. Referring to FIG. 5, a portion of tapered seating tool 10is shown positioned above taper seating connector 22. Additionally,tibial plate 106 and tibial keel 108, which is positioned within tibia110, are also shown. While described and depicted herein with specificreference to tibial plate 106 and tibial keel 108, taper seat tool 10and taper seat connector 12 may be utilized in conjunction with anyorthopedic components having mating male and female tapers. As shown inFIG. 5, tibial plate 106 includes male tapered portion 112 havingaperture 114 extending therethough. Additionally, keel 108 includesfemale tapered surface 116 defining aperture 118 formed therein.

To prepare the various components for attachment, as shown in FIGS. 6-8,keel 108 is first positioned within tibia 110 using any known surgicaltechnique, which may include broaching, reaming, or otherwise preparingan aperture within tibia 110 which is configured to receive keel 108.Once the surgeon is satisfied with the ultimate positioning of keel 108within tibia 110, bone cement 120 may be inserted between tibia 110 andkeel 108. The male tapered portion 112 of the desired tibial plate 106is then positioned within aperture 118 of keel 108. As shown in FIG. 5,taper seating connector 22 may then be inserted through aperture 114 ofthe tibial plate 106 with a portion of shaft 80, including threadedportion 84, extending through aperture 114. With taper seating connector112 positioned within aperture 114 of tibial plate 106, end surface 104(FIG. 3) of bushing 24 will rest against the bottom of counterbore 122of aperture 114.

Once in this positioned, the surgeon may grasp head 20 of fastener 78 oftaper seating connector 22 and rotate the same to cause matingengagement of threads 86 of thread portion 84 with threads 124 formedwithin aperture 118 of keel 108. As head 20 is rotated, fastener 78 willmove further along threads 124 and will eventually contact upper surface102 of bushing 24. Further rotation of head 20 will then begin seatingmale taper 112 with female tapered surface 116, as bushing 24 will beginto move downward, in the direction of arrow B (FIG. 6), with fastener78. Once taper seating connector 22 is sufficiently tightened relativeto keel 108 and plate 104, tapered seating tool 10 may be connected totaper seating connector 22. Specifically, head 20 of taper seatingconnector 22 is positioned within passage 70 of sleeve 16. In thisconfiguration, head 20 is further received by fixed rod 14 via slot 72of catch end 68. As catch end 68 is moved along surface 127 of head 20,bar 74 of catch end 68 is received and retained within catch 76 formedby hook 81 of taper seating connector 22. Advantageously, this designallows taper seating tool 10 to be secured to taper seating connector 22in the position shown in FIGS. 6-8 and, alternatively, in a positionwhich is rotated 180 degrees from the position depicted in FIGS. 6-8.

Once attached as shown in FIGS. 6-8, compression surface 66 of taperedseating tool 10 is in mating engagement with upper surface 102, shown inFIGS. 2 and 7, of bushing 24. Advantageously, once connected to taperseating connector 22, moveable handle 18 of taper seating tool 10 may bemoved to the “locked” position described above. In this position, thestability of taper seating tool 10 along compression surface 66significantly reduces the likelihood of the surgeon moving taper seatingtool 10 and disturbing cement 120. Now, male taper 112 of tibial plate106 and female tapered surface 116 are ready to be fully seated.Referring to FIG. 6, movable handle 38 of taper seating tool 10, shownin FIG. 1, is advanced toward fixed handle 12. As described above,movement of movable handle 38 toward fixed handle 12 results in work arm26 pivoting about link pin 42 and causing rotation of grooves 30 aboutprojections 28 of head 29 of sleeve 16. Rotation of grooves 30 aboutprojections 28 results in a force being exerted on projections 28 ofsleeve 16, causing downward movement of sleeve 16. This force istransferred to upper surface 102 of bushing 24 via compression surface66.

Additionally, as discussed above, exerting a seating force on movablehandle 38 causes work arm 26 to bend along connecting portion 38. Thisbending advantageously transfers the force along the entire length ofconnecting portion 38. Moreover, the bending of connecting portion 38provides a visual indication to a surgeon that a seating force is beingapplied. In one exemplary embodiment, the bending of connecting portion38 of work arm 26 allows moveable handle 18 to physically contact fixedhandle 12 when the proper seating force, e.g., 1000 pounds, has beenapplied to taper seating connector 22. This provides both a visual and atactile indication to a surgeon that a sufficient seating force has beenapplied. Due to the attachment of fixed rod 14 to keel 108, and theability of bushing 24 to move along shaft 80, end surface 104 of bushing24 presses against the bottom of counterbore 122 to force male taper 112into seating engagement with female tapered surface 116 of keel 108.Referring to FIG. 8, male taper 112 of tibial plate 106 is shown seatedwith female tapered surface 116 of keel 108. Thus, tibial plate 106 isin direct contact with keel 108 and space 128 (FIG. 6) is absent.

While this invention has been described as having a preferred design,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

What is claimed is:
 1. A taper seating connector, comprising: a fastenerhaving a shaft and a hooked head, said shaft adapted for connection to afirst orthopedic component having one of a male tapered surface and afemale tapered surface; a bushing retained on and moveable along saidshaft of said fastener, said bushing positioned adjacent a secondorthopedic component when said fastener is connected to the firstorthopedic component, wherein the second orthopedic component has theother of said one of a male tapered surface and a female taperedsurface, whereby movement of one of said fastener and said bushingresults in corresponding movement of one of the first and secondorthopedic components.